DNA polymerase substrate binding site

The DNA polymerase substrate binding site is the catalytic region within DNA polymerase enzymes responsible for the template-directed synthesis of DNA. This site facilitates the precise positioning of the primer-template DNA junction and the incoming deoxyribonucleotide triphosphates (dNTPs) for phosphodiester bond formation (PubMed: 10839320). It plays a fundamental role in cellular processes including genomic replication during the S phase and various DNA repair mechanisms to maintain genetic integrity (UniProt: P12034). In clinical therapeutics, this site is a major target for nucleoside and nucleotide analogs, which compete with endogenous dNTPs for incorporation into the nascent DNA strand (PubChem: CID 135398508). Once incorporated, many of these analogs act as chain terminators because they lack the 3'-hydroxyl group required for the addition of the next nucleotide, thereby halting DNA synthesis and preventing viral replication or cancer cell proliferation (StatPearls: NBK554451). This mechanism is the cornerstone of treatment for various viral infections, including HIV, Hepatitis B, and Herpes Simplex Virus. In oncology, targeting this site with antimetabolites disrupts the rapid DNA synthesis characteristic of malignant cells. Selectivity for viral or tumor polymerases over host mitochondrial DNA polymerase gamma is a critical factor in the safety profile of drugs targeting this site to avoid systemic toxicity (PubMed: 11511042).

Other names

DNA polymerase active sitedNTP binding sitePrimer-template junctionDNA polymerase catalytic pocketReplicating DNA chain

Competitive inhibition of natural dNTP binding and/or induction of DNA chain termination upon incorporation into the nascent DNA strand.